Velocity flow imaging enables angle independent visualization of blood flow, allowing clinicians to visualize and estimate direction and velocity of blood flow in all directions and at any angle. However, today's commercial ultrasound scanners are not able to produce a wall-to-wall delineation of a vessel and present it simultaneously with VFI data superimposed within the entire vessel. FIG. 1 shows a prior art example in which VFI data 102 (the region approximately between dotted straight lines) for a region of interest 104 does not extend to the true walls 106 and 108 (approximated through the dashed straight lines) of a sub-portion 110 of a vessel 112 represented in a B-mode image 114. In this example, regions 116 and 118 between the dashed and dotted lines represent regions in the vessel sub-portion 110 without VFI data.
Furthermore, to obtain the full view of the velocities in the cardiac cycle, clinicians have to manually change parameters such as the pulse repetition frequency (PRF) when examining different magnitudes of velocities. For example, during systole, when higher velocities are present, a higher PRF is needed in order to estimate the right velocities. If the PRF is set too low, aliasing will occur as the blood scatterers are moving too fast to be detected. Unfortunately, it can be a troublesome maneuver to change back and forth between different PRF's at least since the full velocity range cannot be displayed simultaneously. As a consequence, clinicians typically select a static range. However, blood flow outside of the range can contain artifact and/or not even be detected. Unfortunately, this can lead to a misdiagnosis.
Furthermore, the clinician has to manually approximate, e.g., through visual inspection of the B-mode image 114, the location of the vessel walls to place a flow measurement line 120 along a cross-section of the vessel sub-portion 110 from one wall to the other wall for velocity flow measurements. However, this process can be tedious at least since the vessel walls 106 and 108 of the vessel sub-portion 110 are not clearly defined in the B-mode image 114. As a result, the velocity flow measurements may be taken using a part of the vessel sub-portion 110, where no VFI data is present (e.g., regions 116 and/or 118), and/or part of the anatomy outside of the vessel sub-portion 110 (e.g., non-vessel anatomy). Unfortunately, this may lead to erroneous and/or inaccurate flow measurements.